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d0781c95bc
The DSA (Distributed Switch Architecture) implementation has made a
design decision when it got introduced to the Linux kernel in 2008.
That was to hide away from the user the CPU-facing Ethernet MAC, since
it does not make sense to register it as a struct net_device (UCLASS_ETH
udevice for U-Boot), because that would never be beneficial for a user:
they would not be able to use it for traffic, since conceptually, a
packet delivered to the CPU port should loop back into the system.
Nonetheless, DSA has had numerous growing pains due to the lack of a
struct net_device for the CPU port, but so far it has overcome them.
It is unlikely at this stage of maturity that this aspect of it will
change.
We would like U-Boot to present the same information as Linux, to be at
parity in terms of number of interfaces, so that ethNaddr environment
variables could directly be associated between U-Boot and Linux.
Therefore, we would implicitly like U-Boot to hide the CPU port from the
user as well.
But the paradox is that DSA still needs a struct phy_device to inform
the driver of the parameters of the link that it should configure the
CPU port to. The problem is that the phy_device is typically returned
via a call to phy_connect, which needs an udevice to attach the PHY to,
and to search its ofnode for the 'fixed-link' property. But we don't
have an udevice to present for the CPU port.
Since 99% of DSA setups are MAC-to-MAC connections between the switch
and the host Ethernet controller, the struct phy_device is going to be a
fixed PHY. This simplifies things quite a bit. In U-Boot, a fixed PHY
does not need an MDIO bus, and does not need an attached dev either.
Basically, the phy_connect call doesn't do any connection, it just
creates the fixed PHY.
The proposal of this patch is to introduce a new fixed_phy_create
function which will take a single argument: the ofnode that holds this:
port@4 {
reg = <4>;
phy-mode = "internal";
fixed-link {
speed = <2500>;
full-duplex;
};
};
and probe a fixed PHY driver using the information from this ofnode.
DSA will probably be the only user of this function.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
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| .. | ||
| aquantia.c | ||
| atheros.c | ||
| b53.c | ||
| broadcom.c | ||
| ca_phy.c | ||
| cortina.c | ||
| davicom.c | ||
| dp83867.c | ||
| et1011c.c | ||
| fixed.c | ||
| generic_10g.c | ||
| Kconfig | ||
| lxt.c | ||
| Makefile | ||
| marvell.c | ||
| meson-gxl.c | ||
| micrel_ksz8xxx.c | ||
| micrel_ksz90x1.c | ||
| miiphybb.c | ||
| mscc.c | ||
| mv88e61xx.c | ||
| mv88e6352.c | ||
| natsemi.c | ||
| ncsi.c | ||
| phy.c | ||
| realtek.c | ||
| smsc.c | ||
| teranetics.c | ||
| ti_phy_init.c | ||
| ti_phy_init.h | ||
| vitesse.c | ||
| xilinx_gmii2rgmii.c | ||
| xilinx_phy.c | ||